The present invention relates to a method of fiber spitting and, more particularly, to a method of fiber splitting for conjugated fiber, which is executed by differentiating crystallinities of polymers. Further particularly, the present invention is concerned with a method of fiber splitting for conjugated fiber by adding a nucleated agent, a releasing agent or a catalyst into any one of the polymers of manufacturing the conjugated fiber, or by differentiating the viscosity of the polymers during the process of manufacturing the conjugated fiber, or raising a winding speed of the fiber after a spinning process.
For a purpose of conveniently describing the methods of fiber splitting, the materials chosen for use in the conventional methods and the method in accordance with the present invention which will be described below are limited to be polyamides or polyesters, however, these limited materials should not be deemed to be a restriction of the invention.
There are two conventional methods widely used in fiber splitting of conjugated fiber, which are firstly a method of fiber splitting by physical treatment (or fiber splitting by mechanical treatment) and secondly, a method of fiber splitting by chemical treatment. Referring to FIG. 1, the method of fiber splitting by physical treatment comprises five steps listed hereinbelow:
a) preparing polyamides and polyesters with a conventional chemical reaction; PA1 b) spinning: referring to FIG. 2, charging polyamide 10 and polyester 20 into respective extruders 30 and heating therein to melt them and then being extruded into a spin pack 32 via a metering gear pump 31. Polyamide 10 and polyester 20 are discharged from the metering gear pump 31 and the spin pack 32 by a winding machine 70 at a speed of 500-1500 meter/minute via a quenching zone 40, a drawing zone 50 and a heat setting zone 60 to form a conjugated fiber 80 as shown in FIG. 3. PA1 c) fiber splitting by false twisting: twisting the conjugated fiber 80 at a speed of 200 twists/minute and then proceeding with a false twisting step at an overfeed rate about 0.5% and a heating temperature around 180 degrees centigrade in order to let the conjugated fiber 80 possess two different features of shrinkage and elongation, such that the conjugated fiber 80 is in a loosened state. PA1 d) weaving; and PA1 e) dyeing and finishing. PA1 i) the fiber is easily slitted before proceeding with the weaving process, which results in a lower strength and makes the fiber in a crimped state, therefore causes a frequent breaking of the fiber, and this will cause an interruption during the weaving process, which is adverse to the entire manufacturing process. PA1 ii) the split conjugated fiber does not have a uniform constructure strength, which will reduce the duty life of the conjugated fiber. PA1 a) preparing polyamide and polyester; PA1 b) spinning the polyamide and polyester into a conjugated fiber; PA1 c) weaving; PA1 d) mercerizing: adding NaOH to the conjugated fiber to dissolve partial of the polyester portion of the conjugated fiber; PA1 e) rinsing: to wash NaOH out from the conjugated fiber; and PA1 f) dyeing and finishing. PA1 i) because the conjugated fiber has a good feature of absorption, there is still some NaOH maintained in the conjugated fiber after the rinsing step and which will make the greige slightly yellow which will result in some dyeing problems thereafter and there is difficulty in removing all oligomers produced after mercerizing step, which will pollute the dyeing house. PA1 ii) for different types of combination of the conjugated fiber, such as the combination of circular, tubular, triangular, square and hexagonal cross-section fibers, the difference of the mercerizing speed will cause one of the polyamide or polyester to be mercerized severely, the constructure strength of the conjugated fiber is thus decreased. PA1 iii) the quality of the conjugated fiber is dependent on the rate of the mercerizing process, 1% of the rate difference of mercerizing will make the feel of touch very different. Thus, the rate difference of mercerizing process should not generally be over 13%. PA1 iv) the storing stability of the chemical agents used in the method of chemical treatment, the safety guarantee and homogeneity during operation, and the required cooling conditions for the chemical agents, the treatment of the exhausted solution after the rinsing step and so on are serious problems with regard to environmental consideration and the expenditure thereof. PA1 i) preparing polymers: charging a first polymer and a second polymer respectively into corresponding extruders and adding a nucleated agent or a releasing agent or a catalyst into one of the first or second polymers to differentiate the crystallinity between the first and the second polymers, or to differentiate the crystallinity between the first and second polymers by adjusting the viscosity through controlling the temperature; PA1 ii) spinning: the first and second polymers are transferred to a spinning zone and are spun at a winding speed of 3000 to 8000 meters per minute to be a conjugated fiber via a spin pack in which there is a plurality of orifices defined in an under side; PA1 iii) weaving; and PA1 iv) dyeing and finishing.
However, such a method has the following drawbacks:
Referring to FIG. 4, the method of fiber splitting by chemical treatment includes six steps:
Such a method by chemical treatment is better than the method by physical treatment but still has the following drawbacks:
Therefore, there has been a long and unfulfilled need for a method of fiber splitting for conjugated fiber to solve the above-mentioned problems.